I build the F5 turbo with low rails +/- 15V for driving a low impedance ribbon speaker.
Everything looks fine bandwidth 750Khz -3dB and I get about 35A from the output in this configuration.
I use 4 sets mosfets from IR the IRFP240 and IRFP9240 and 0,235 Ohm source resistors.
The fronted is the same as the F5 with 100 Ohm parallel in the feedback loop.
Now the problem if I feed the amplifier 100Khz and on the output the voltage rise above 20Vtt then the output collapse and the fets drawing lots of current about 10A each.
It doesn't mind if I load the output with a resistor or not.
What could be the problem.
I tried capacitors on the feedback resistors to reduce the bandwidth to 100Khz use input filter and 1N from drain to gate.
Nothing helps.

Unability of the front end to supply enough current to properly swing the output mosfet's gate capacitance at such high freq ? this leading to what class D people call shoot through, ie N and P channel mosfets conducting too much at the same time, ie shorting V+ to V-

Unability of the front end to supply enough current to properly swing the output mosfet's gate capacitance at such high freq ? this leading to what class D people call shoot through, ie N and P channel mosfets conducting too much at the same time, ie shorting V+ to V-

Regards,
--
stéphane

Hi stéphane

Should I leave it like that and pay no attention to it or can it cause problems.